Eleventh Year. 

 Vol. XXII. No. 550. 



AUGUST 18, 1893. 



Single Copies, Ten Cents. 

 $3. 50 Per Year, in Advance. 



Contents. 



Botany in Jamaica. J. E. Humphreys 



Introduction of Weeds in Grass Seeds. T 



A. Williams 



Periodical Cicada. C. V. Riley..!'.'.'.'.'.'.'.'.'.'.'.!]" 



Notes and News 



The Atmosphere of Stel'l'a'r "Sp'a'ce.'"G'."D'. 



Li veing 



Fish Acclimatization on the Pacific 'Coa's't'.' ' H. 



M. Smith 



Technical Education. Alexander 'Meek 



Palenque Hieroglyphics. Ph. J. J. Valentini... 



Humboldt and Brazil 



Remarks on the Terns of Little "c're'en" Isl 



land, Maine. Arthur H. Norton 

 An Analcite Copper Bowlder from the Kewee- 

 naw Range, Michigan, E. O. Hovey 



•Loew's Natural System of the Actions of Poi- 

 sons. T- C. Bay 



Some Ohio Slounds. Harold Heath . 

 An Eye Protector to Be Used with the Monocu- 

 lar Microscope. L. B. Hall 

 Letters to the Editor, 



Birds That Sing By Moonlight. J, B. Lewis. 

 The Cambojan Khmers, 0, S, Wake 



Oregon Wax. Charles Piatt 



Bacteria in Hens' Eggs. C. T. McClintock. 

 Correlation of Tejon Deposits with Eocene 



Stages of the Gulf Slope. G. D, Harris 

 An Addition to the Myology of the Cat t 

 W. Thompson 



THE WINNIPEG COUNTRY; 



The Ornamental Penman's Pocketbook of Alpha- 

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 draftsmen, 20 cts. A System of Easy Lettering, by 

 Howard Cromwell, 60 cts. Practical Electrics : A 

 Universal Handybook on Every-day Electrical Mat- 

 ters, 135 pp., fully illustrated, ISmo, cloth, 75 cts. 

 Notes on Design of Small Dynamo, by G. HaUiday, 



ROUGHING IT WITH AN ECLIPSE PARTY. ^^''i^:%l^^^^rIn'6'''k%Tt!''ct'^^^^^ 



A. ROCHESTER FEL.LOW. 



(S. H. SCUDDER.) 



With thirty-two Illustrations and a Map. 

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W. Gillett, 87 pp., 12 folding plates, ISmo, cloth, %i 

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 Bos 151, Manchester, N. H. 



NEW METHOD OF PROTECTING BUILDINGS FROM LIGHTNING. 



SPARE THE ROD AND SPOIL THE HOUSE! 



Lightninff Destroys, Shall It be Your JSou 



I JPouiid of Copper? 



PROTECTION FROM LIGHTNING. 

 What is the Problem ? 



In seeking a means of protection froai ligtituiug-disctiarges, we have In view 

 two objects,— the one the prevention o! damage to buildings, and the other 

 the prevention of Injury to life. In order to destroy a building lu whole or la 

 part, it Is necessary that worli should bo done ; that is, as physicists express 

 it, energy is required. Ju^t before the lighming-discharge takes place, the 

 energy capable of doing the damage which sve seek lo prevent exists In the 

 column of air extending from the cloud to the earth In some form that makes 

 it capable of appearing as what we call electricity. We will therefore ca'I It 

 electrical energy. What this electrical energy is, It Is not necessary for us to 

 consider In this place; but that It exists there can be no doubt, as it manifests 

 itself In the destruction of buildings. The problem that we have to deal with, 

 therefore. Is the conversion of this energy Into some other form, and tho ac- 

 complishment of this in such a way as shall result In the least injury to prop- 

 erty and life. 



Why Have the Old Rods Failed? 



When lightning-rods were first proposed, the science of energetics was en- 

 tirely undeveloped; that is to say, in the middle of the last century scientific 

 men had not come to recognize the fact that the different forms of energy — 

 heat, electricity, mechanical power, etc.— were convertible one Into the other, 

 and that each could produce just so much of each of the other forms, and no 

 more. The doctrine of the conservation and correlation of energy was first 

 clearly worked out In the early part of this century. There were, however, 

 some facts known In regard to electricity a hundred and forty years ago; and 

 among these were the attracting power of points for an electric spark, and the 

 conducting power of metals. Lightning-rods were therefore Introduced with 

 the idea that the electricity exlsting_ In the lightning-discharge could be coa- 

 veyed around the building which it was proposed to protect, and that the 

 building would thus be saved. 



The question as to dissipation of the energy Involved was entirely Ignored, 

 naturally; and from that time to this, in spite of the best endeavors of those 

 Interested, lightning-rods constructed iu accordance with Franklin's principle 

 have not furnished satisfactory protection. The reason for this U apparrnt 

 when It is considered that the electrical energy existing In the atmosphere 

 before the discharge, or, more exactly. In the column of dielectric from the 

 cloud to the earth, above referred to, reaches Its maximum value on the sur- 

 face of the conductors that chance to be within the column of dielectric ; so 

 that the greatest display of energy will be on the surface of the very lightning- 

 rods that were meant to protect, and damage results, as so often proves to be 

 the case. 



It will be understood, of course, that this display of energy on the surface 

 of the old lightning-rods Is aided by their being more or less Insulated from 

 the earth, but In any event the very existence of such a mass of metnl as an 

 old lightning-rod can only tend to produce a disastrous dissipation of electrical 

 energy upon Its surface, — " to draw the lightning," as it Is so commonly put. 



Is there a Better Means of Protection ? 

 Having cleared our minds, therefore, of any idea of conducting electricity, 

 and keeping clearly in view the fact that in provldlug protection against light- 

 ning we must furclsh some means i-y which tiie electrical energy may be 

 harmlessly dissipated, the question ariB[\s, " Can an Improved form be. given 

 to the rod so that It shall aid In this dissipation ? " 



As the electrical energy Involved manifests itself on the surface of conduc- 

 tors, the Improved rod should be metallic; but, Instead of making a large rod, 

 suppose that we make It comparatively small in size, so that the tola! amount 

 of metal running from the top of the house to some pi.iut a little below the 

 foundations shall not exceed one pound. Suppose, again, th.i.t we Introduce 

 numerous Insulating joints in this rod. We shall then have a rod that experi- 

 ence shows will be readily destroyed — will be readily dissipated —when a 

 discharge takes place; an i It will be evident, that, so far as the electrical en- 

 ergy Is consumed In doing this, there will be the less to do other damage. 



The only point that remains to be proved as to the utility of such a rod Is to 

 show that the dissipation of such a conductor does not tend to injure other 

 bodies Inits Immediate vicinity. On this point I can only say that I have 

 found no case where such a conductor (for instance, a bell wire) has been dis- 

 sipated, eveu If resting against a plastered wall, where there has been any 

 material damage done to surrounding objects. 



Of course, it Is readily understood that such an explosion cannot take place 

 In a couflned space without the rupture of the wails (the wire cannot be 

 boarded over); but in every case that I have found recorded this dlssipatiou 

 takes place just as gunpowder burns when spread on a board. The objects 

 against wi.ich tho couduc-tor rests may be stained, but they are not shattered, 



I would therefore make clear this distinction between the action of electri- 

 cal energy when dissipated en the surface of a large conductor and when dis- 

 sipated oi^the surface of a comparatively small or easily di-sipated conductor 

 When dissipated on the surface of a large conductor, — a conductor so strong 

 as to resist the explosive effect, — damage results to objecis around. When 

 dissipated on the surface of a small conductor, the conductor goes, but the 

 other objects around are saved 



A Typical Case of the Action of a Small Conductor. 



Franklin, in a letter to Coiilnson read before the London Royal Society 

 Dec. 18, 1755, describing the partial destruction by lightning of a church-tower 

 at Newbury, Mass., wrote, "Near the bell was fixed an iron hammer to strike 

 the hours ; and from the tail of the hammer a wire went down through a small 

 gimlet-hole in the floor that the bell stood upon, and through a second floor m 

 like manner; then horizontally under and near the plastered celling of that 

 second floor, till it came near a plastered wall ; then down by the side of that 

 wall to a clock, which stood about twenty feet below the bell. The wire was 

 not bigger than a common knitting needle. The spire was split all to pieces 

 by the lightning, and the parts flung in all directions over the square in whiit 

 the church stood, so that nothing remained above the bell. The llgbtrir<> 

 passed between the hammer and the clock in the above-mentioned wire 

 without hurting either of the floors, or having any effect upon them (excerpt 

 making the gimlet-holes, through which the wire passed, a little bigger), end 

 without hurting the plastered wall, or any part of the building, so far as the 

 aforesaid wire and the pendulum-wire of the clock extended; which latter 

 wire was about the thickness of a goose-qulli. From the eud of the pendu- 

 lum, downqulte to the ground, the builJnig was exceedingly rent and dam- 

 aged. . . . No part of the aforementloued long, small wire, between the clock 

 and the hammer, could be found, except about two inches that hung to the 

 tail of the hammer, and about as much that was fastened to the clock : the 

 rest being exploded, and its particles disalpated In smoke and air, as gun- 

 powder 13 by common fire, and had only left a black smutty track on the plas- 

 tai lug, three or four inches broad, darkest in the middl?, and fainter towards 

 the edges, all along the celling, under which it passed, and down iho wall. ' 



One hundred feet of the Hodges Patent Lightning Dlspeller (made under 

 patents of N. D. C. Hodges. Editor of Science) will be nailed, postpaid, to any 

 address, on receipt of Ave dollars ($5). 



Correspondence wUcitecl. Agents tcanted. 



AMERICAN LIGHTNING PROTECTION CO. 



874r Broad-way, New York Citv. 



